SARS-CoV-2 omicron variants succumbin vitrotoArtemisia annuahot water extracts

Abstract

The SARS-CoV-2 (COVID-19) global pandemic continuous to infect and kill millions while rapidly evolving new variants that are more transmissible and evading vaccine-elicited antibodies. Artemisia annua L. extracts have shown potency against all previously tested variants. Here we further queried extract efficacy against omicron and its recent subvariants. Using Vero E6 cells, we measured the in vitro efficacy (IC50) of stored (frozen) dried-leaf hot-water A. annua L. extracts of four cultivars (A3, BUR, MED, and SAM) against SARS-CoV-2 variants: original WA1 (WT), BA.1.1.529+R346K (omicron), BA.2, BA.2.12.1, and BA.4. IC50 values normalized to the extract artemisinin (ART) content ranged from 0.5-16.5 uM ART. When normalized to dry mass of the extracted A. annua leaves, values ranged from 20-106 ug. Although IC50 values for these new variants are slightly higher than those reported for previously tested variants, they were within limits of assay variation. There was no measurable loss of cell viability at leaf dry weights less than or equal to 50 ug of any cultivar extract. Results continue to indicate that oral consumption of A. annua hot-water extracts (tea infusions) could potentially provide a cost-effective approach to help stave off this pandemic virus and its rapidly evolving variants.

Artemisinin as a therapeuticvs.its more complexArtemisiasource material

“…Several groups have reported that extracts of A. annua and A. afra have potent anti-SARS-CoV-2 activity. 25,26,28–30 All testing thus far has been in vitro using hot water and/or solvent extracts of A. annua .…”

“…Nair et al has continued to test the original (frozen) DLAe samples for efficacy against emerging SARS-CoV-2 variants including delta, 26 omicron, and BA.4 30 and to date the A. annua hot water extracts have remained potent. Although thus far there is no identification of the non-artemisinin active phytochemicals, there are several likely candidates including isorhamnetin, luteolin, and rosmarinic acid, which are present in A. annua with IC 50 values of 8.42, 11.81, and 9.43 μM, respectively, against 3CLpro, the main chymotrypsin-like protease involved in SARS-CoV-2 viral replication.…”

The mint versus Covid hypothesis

“…If caffeic acid is a principal antiviral agent (or an effective proxy for antiviral activity) then Gecofure should have greater antiviral potency than Spice. This would be reminiscent of the situation for sweet wormwood (Artemisia annua) and African wormwood (Artemisia afra), which contain high or low amounts of artemisinin, respectively [44][45][46].…”

“…It has also been shown that the use of whole plant preparations could help combat the emergence of artemisinin-resistant parasites because the crude mixture contains a range of additional antimalarial compounds that complement or synergize with artemisinin [41][42][43]. Wormwood leaf preparations, including preparations of Artemisia species that don't contain artemisinin, have also been shown to block SARS-CoV-2 infection at a step downstream of infectious entry in cell culture systems [44][45][46][47].…”